In a heat exchanger, an intercooler is an apparatus for cooling compressed air at a high temperature and a high pressure by a supercharger to increase an output of an engine.
The air rapidly compressed by the supercharger becomes extremely high in temperature and thus a volume of the compressed air is expanded and an oxygen density reduces, resulting in a reduction in charging efficiency in the cylinder. Therefore, the intercooler cools the high-temperature air compressed by the supercharger to increase suction efficiency of the engine cylinder and increase combustion efficiency, thereby increasing fuel efficiency.
The intercooler in charge of the role may be divided into water-cooled type and air-cooled type according to a cooling method. Among those, a principle of a water-cooled intercooler 10 is similar to that of an air-cooled intercooler, but the water-cooled intercooler 10 differs from the air-cooled intercooler in that it cools the compressed air using cooling water of a vehicle, water or the like instead of using external air when cooling the intercooler through which the high-temperature air passes.
The water-cooled intercooler 10 illustrated in FIG. 1 includes a first header tank 20 and a second header tank 30 disposed in parallel while being spaced apart from each other by a predetermined distance; a first inlet pipe 40 formed in the first header tank 20 and having air introduced therethrough and a first outlet pipe 50 formed in a second header tank 30 and having the air discharged therethrough; a plurality of tubes 60 having both ends fixed to the first header tank 20 and the second header tank 30 to form air passages; fins 70 interposed between the tubes 60; a cover member 80 having an assembly of the tubes 60 and the fins 70 housed therein and opened on one side surface and the other side surface where one end part of the tube 60 is located; and a second inlet pipe 41 formed on one side surface of the cover member 80 and having cooling water introduced therethrough and a second outlet pipe 51 formed on one side of the cover member 80 and having the cooling water discharged therethrough.
On the contrary, the water-cooled intercooler 10 may be configured to pass cooling water through an inside of a tube and include a case having a heat exchanger core disposed therein and surrounding the core, with the heat exchanger core being an assembly in which a header tank, a tube, and a fin are assembled, and be cooled by the core while air passing through an inner side of the case.
However, such a water-cooled intercooler can prevent air from passing between the inner side of the case and an outer side of the core to pass all the air through the core, thereby improving the heat exchange efficiency. However, since the outer side of the case and the outer side of the core are spaced apart from each other in order to insert and assemble the core into the inner side of the case, the air may be bypassed through the space between the case and the core to lower the heat exchange performance. Alternatively, in order that the inner side of the case and the outer side of the core are in close contact with each other without being spaced apart from each other, the case should be formed into several pieces and then assembled. As a result, the structure and assembly may be complicated and the structural strength of the case may be reduced.